Tilting furnace

ABSTRACT

A tilting furnace has non-tiltable electrodes through its roof. The bottom portion of the furnace has supporting rolls arranged on both sides of a vertical line through the center of gravity of the furnace when the furnace is in upright position, and cradle beams at the sides of the supporting rolls. For deslagging without moving the electrodes, the furnace may be rotated through small angles around a stationary fulcrum near the roof with the supporting rolls rolling on a base. Beyond these small angles, the electrodes are withdrawn and the furnace may move laterally onto the cradle beams to roll further over on the base.

United States Patent 1 1111 3,835,231 Marchner 1 Sept. 10, 1974 [541TILTING FURNACE I 3,035,106 5/1962 Mercier 13 10 [75] Inventor: JanMarchner, Vasteras, Sweden Primary Examiner R. N. Ema, Jr [73] Assignee:Allmanna Svenska Elektriska Attorney, Agent, or Firm-Kenyon & KenyonReilly Aktiebolaget, Vasteras, Sweden Carr & Chapin 22 F'] d: No 9, 19721 i v 57 ABSTRACT [21] A 304894 A tilting furnace has non-tiltableelectrodes through its roof. The bottom portion of the furnace has sup-[30] Foreign Application Priority Data porting rolls arranged on bothsides of a vertical line Nov. 9, 1971 Sweden 14265/71 through the CenterOf gravity of the furnace When the furnace is in upright position, andcradle beams at the [52 US. Cl. 13/10 Sides 0 the pp g rolls- Ferdeslagging without [51] Int. Cl. F27b 14/02 moving the electrodes, thefurnace y be rotated [58] Field of Search 13/10 through Small anglesaround a Stationary fulcrum hear the roof with the supporting rollsrolling on a base. Be- 5 References Cited yond these small angles, theelectrodes arewithdrawn UNITED STATES PATENTS and the furnace may movelaterally ontothe cradle beams to roll further over on the base.1,313,890 8/1919 Gray l3/l0 1,417,303 5/1922 Nolly 13/10 4 Claims, 3Drawing Figures ,a vertically adjustable furnace roof and non-tiltableelectrodes extending through the roof.

Such furnaces are often constructed with a bottom having two or morearcuate cradle beams, the furnace with its teeming spout being movedlaterally by rolling action to a teeming place when the furnace istilted. This system involves the disadvantage that the electrodes mustbe lifted out of the roof not only for teeming the melt from the furnacebut also when the furnace is insignificantly tilted, for example, to adeslagging postion requiring only slight tilting movements, where themelt surface is at most level with a slag opening or the lower edge ofthe teeming opening. From a metallurgical point of view it is oftennecessary to have the heating effect on when the tilting angle of thefurnace is small. Also, it is not practical to have to remove theelectrodes in connection with suchsmall tilting movements, often belowin relation to the center-ofgravity line when the furnace is in uprightposition.

There are also tilting furnaces with a bottom portion containing rollsor several sets of rolls, and in this case the tilting can take placeround a fulcrum close to the furnace roof, and when. the tilting anglesare small the electrodes can be maintained in position. A disadvantageof this type of tiltability is that the furnace teeming spout, when intilting position, will come too close to the base of the furnace,because no lateral movement is involved by the rotation, and where thereis often no place for ladles and the like.

SUMMARY OF THE INVENTION The invention aims at a solution to theabovementioned problem and is characterized in that the bottom portionof the furnace partly comprises an arcuate series of supporting rollsrolling against a base and arranged along an arcuate track extendingfrom both sides of a vertical line through the centre of gravity of thefurnace when in upright position, and partly has arcuate cradle beamsbeside the track of the supporting rolls, connected at least on one sideto said track, the furnace, when exposed to small movements on bothsides of the center-of-gravity line when in upright position, beingrotated round a stationary pivoting point located close to the furnaceroof, after which outside these rotaryv motions the furnace rolls on thecradle beams against a preferably plane base. In this way, small rotarymotions can be made, for example between and 10 relative to thecenter-of-gravity line, round a fulcrum near the roof, and this meansthat the electrodes can be held stationary, for example, duringdeslagging. When the furnace is further tilted, the electrodes must bedrawn from the roof because the furnace moves laterally and rolls on thearcuate cradles.

THE DRAWINGS PREFERRED EMBODIMENT An arc furnace is shown in FIG. 1 witha furnace vessel 11 and a roof 12 with vertically adjustable consumableelectrodes 13 through the roof. The bottom portion of the vessel isprovided with supporting rolls 14 close to and extending on both sidesof a line 16 through the center of gravity when the furnace is inupright position, said supporting rolls being arranged in an arcuatetrack 15 on the vessel's bottom, either in the form of two transverselyinterspaced sets of separate rolls, one for each supported part of thefurnace, or as one set of longer rolls extending transversely along thewhole bottom of the vessel. The track for the supporting rolls extendsbetween the rotational angles a =+l0 and a l0 in relation to thecenter-of-gravity line 16. The rolls 14 are locked by means of a catch(not shown) when the arcuate cradles take over the rollingoff during thecontinuous tilting.

At least two arcuate cradle beams 21 are arranged on the bottom of thevessel 11 on one or both sides of the track 15 of the supporting rolls14, and are connected to it, and on said cradle beams the furnace vesselrolls or is rolled when turned above the shown a-values 10). Theelectrodes 13 must, however, first be lifted up from the roof because ofthe lateral movement taking place when the furnace vessel is rolled.During rotation on the arcuate base of supporting rolls, the vessel isturned round a center 17 close to the roof l2, and the electrodes canbeheld stationary. In other words, the arcuate series of rolls l4 andtheir arcuate track 15 are concentric with this center 17. The center ofturning lies here at the upper edge of the roof, but slight deviationsfrom this can easily be made.

FIG. 2 shows one supporting roll 14 arranged in a U- formed arcuatetrack 15 in the bottom portion of the furnace vessel 11. The roll 14 issupported against the base 19 along a horizontal rolling track 18connected to and elevated above the horizontal base 19 onto which therocker beam 21 rolls for further tilting of the vessel 11. The base 19can be supported by cars 20 (FIG. 1) so that the vessel 11 can bemovable for casting operations (see arrows A in FIG. 1). The rolls andthe cradle beams can of course change places.

a It is suitable to arrange two or three separate cradle beams 21 underthe vessel in connection with the supporting rolls l4 (suitably one setof supporting rolls for each separate cradle beam).

In FIG. 3 is shown how the supporting rolls 14 are moved to the left inthe track 15 during turning to the left, for left-hand rotation of thevessel about the center 17, the vessels bottom swinging in a right-handdirection to adjust the melting level in the furnace for deslaggingthrough a rear slag opening (see at 22), or at the tapping opening 23.The centerline 16 is here at position 16a.

The cradle beam is moved from position 21 to 21" ,when the vessel isturned 10 to the left (FIG. 3) with its centerline l6 rotated toposition 16a. A supporting roll has then moved in each instance thedistance b, and the rolls are farthest to the left in the channel 15.When the furnace changes to supporting by means of the cradle beam andthus rolling, upon further rotation in a left-hand direction, the beam21 and the track 15 are arranged in such a way that a small change oflevel is obtained or a shoulder or nib (not shown) must be passed, andthis means a little extra tilting resistance until the rolling isstarted. After this the supporting rolls release their hold of the base19 and are kept in position by means of a catch (not shown).

To explain further, note that in FIG. 3 the rolling track 18 ends with ashoulder 18a and the cradle beam 21 ends to form a shoulder 21a, andthat these shoulders abut when the furnace vertical centerline isrotated to the 16a position. When these shoulders are separated thefurnace tilting mechanism 25 can only cause rotation of the furnace,swinging the line 16 from 16 to 16a position about the point 17. Thelower tip of the shoulder 21a, due to the arcuate beam shape, contactsthe base 19 only when .the two ends abut. When forced to abut bycontinued thrust on the furnace by the mechanism 25, the furnace isforced to roll over on its cradle beams, lifting the rolls 14 from theirrolling track 18 with the shoulder 21 moving arcuately upwardly. Uponreverse rocking, the two shoulders return together while the rolls 14return to their rolling track 18, the furnace thereafter rotating aboutthe center 17 adjacent to the electrodeswith the shoulders separatingagain and the cradle beam 21 and the tip 210 of its shoulder, free fromthe base 19.

As previously noted, there must be two interspaced cradle beams 21 whichthe furnaces bottom partly has; in other words, these cradle beamsprovide stabilityand extend in the desired rolling direction of thefurnace, and terminate near to the furnaces vertical centre line 16. Thecradle beams connect with the arcuate track 15, both being formed by orconnected to the furnaces bottom. The arcuate track 15 extends on bothsides of this centerline 16 a distance giving the desired extent ofrotation about the center 17. The rolls may each transversely span thedistance between the cradle beams or be two series of short rolls eachvbeside one of the cradle beams. in either instance, the arcuate track ortracks 15 should be designed accordingly.

During tilting (rolling) along the cradle beams 12, the tapping spout 24is moved laterally and a suitable tapping position is obtained (largerturning then a 10). See at arrow B in FIG. 1.

The supporting rolls can be arranged also in other ways than accordingto FIG. 2 and can possibly be made so as to extend along the whole base.The number of supporting rolls in this case is five, of which only threeare represented in FIG. 3, but the number may vary between three andupwards, but not less than that. The change from supporting by the rollsto rolling on the cradle takes place at the desired small angle a.

may, for example, be chosen to be between and here l0 has beenpreferred. Also 8 is feasible. The tilting machinery 25 can behydraulic, pneumatic or electrical.

The invention can be varied in many ways within the scope of the belowclaims. For example, the group of rolls 14 can be held together, asindicated at 14a, as in the manner of the rolls of roller bearings ingeneral, and, further, may be suitably retained in the track 15. Theseengineering details are easily within the skill of any competent furnacedesigner.

Iclaim:

1. A tilting furnace which can be tilted far enough for teeming andhaving a roof in which non-tiltable electrodes are positioned andtilting means; wherein the improvement comprises means for supportingsaid furnace for rotation about a center at least adjacent to saidelectrodes and within a limited range of rotative angularities less thanpermits teeming, and means for supporting said furnace for bodilyrolling over when tilted beyond said range, for teeming.

2. The furnace of claim 1 in which said rotative supporting meanscomprise a series of rolls and a track therefor which is connected tothe furnaces bottom and is arcuately concentric with said center andextends from both sides of the furnaces vertical centerline, and saidbodily rolling means comprise cradle beams connected to and extendingpartly around the furnaces said bottom in the direction the furnace istilted for teeming, and bases on which said rolls and beams arerespectively supported.

3. The furnace of claim 2 in which the base for saidrolls is at a higherlevel than the base for said beams and terminates to form a dependingshoulder and the ends of said beams adjacent to the rolls base shoulderterminate to form an upstanding shoulder, the two shoulders beingrelatively positioned so that they are free from each other duringrotation of said furnace within said rotative angularity range and saidbeams are free from their base, but abut when said range is exceeded inthe furnaces teeming tilting direction by operation of said tiltingmeans so that said furnace is forced to roll over on said beams forbodily rolling, said rolls being free to lift from their base when thebeams rollover on their base.

4. The furnace of claim 3 in which said rotative angularity range isfrom 5 to 20 on at least one side of the furnaces centerline.

1. A tilting furnace which can be tilted far enough for teeming andhaving a roof in which non-tiltable electrodes are positioned andtilting means; wherein the improvement comprises means for supportingsaid furnace for rotation about a center at least adjacent to saidelectrodes and within a limited range of rotative angularities less thanpermits teeming, and means for supporting said furnace for bodilyrolling over when tilted beyond said range, for teeming.
 2. The furnaceof claim 1 in which said rotative supporting means comprise a series ofrolls and a track therefor which is connected to the furnace''s bottomand is arcuately concentric with said center and extends from both sidesof the furnace''s vertical centerline, and said bodily rolling meanscomprise cradle beams connected to and extending paRtly around thefurnace''s said bottom in the direction the furnace is tilted forteeming, and bases on which said rolls and beams are respectivelysupported.
 3. The furnace of claim 2 in which the base for said rolls isat a higher level than the base for said beams and terminates to form adepending shoulder and the ends of said beams adjacent to the rolls''base shoulder terminate to form an upstanding shoulder, the twoshoulders being relatively positioned so that they are free from eachother during rotation of said furnace within said rotative angularityrange and said beams are free from their base, but abut when said rangeis exceeded in the furnace''s teeming tilting direction by operation ofsaid tilting means so that said furnace is forced to roll over on saidbeams for bodily rolling, said rolls being free to lift from their basewhen the beams roll over on their base.
 4. The furnace of claim 3 inwhich said rotative angularity range is from 5* to 20* on at least oneside of the furnace''s centerline.